"We were notified and we urged the Turkish government to limit their operations to precise targeting of the PKK, to limit the scope and duration of their operations," White House spokesman Scott Stanzel said.

"We urged them to work directly also with the Iraqis, including Kurdish government officials, in determining how best to address the threat of the PKK," Stanzel said.

The Turkish military said Friday that it launched air strike and shelling on Thursday on the PKK targets in northern Iraq.

It sent ground troops in the region Thursday evening and "will return to Turkey after it achieves the planned targets," the statement said.

The United States has voiced support for Turkish strikes against the PKK, but meanwhile called for cooperation between Turkey and Iraq.